The present invention relates to a radial flow fan, in particular for the air-conditioning of a motor vehicle.
A number of fans of this type are known in the art.
Thus, for example, the Pat. No. FR-2 471 503 discloses a radial-flow fan comprising a volute housing in which is disposed a ventilation wheel connected to driving means. The wheel has a series of vanes each having an outer edge and an inner edge and extending in a direction roughly parallel to the axis of rotation of this wheel, from a bowl connecting the vanes to the driving means, to an edge of an air intake defining with the bowl a space for a fluid stream.
All these devices have a number of drawbacks.
Indeed, as the efficiency of such fans is relatively low, the driving means are formed by two-pole electric motors whereby it is possible to drive the ventilation wheel at a relatively high speed of rotation to compensate for this low efficiency while retaining the same overall size. These two-pole motors have a relatively great axial length, which makes it necessary, in order to limit the total overall size of the fan, to use a greatly bulging impeller bowl. This results in a further drop in the efficiency of the unit.
Lastly, the efficiency of this type of motor is relatively low and it has a tendency to heat up so that it is necessary to provide a cooling device for this motor. An example of such a cooling device is described in the aforementioned patent.